Some of us old enough to remember the old "Twilight Zone" on televion may remember some of the scarier visions of Rod Serling's universe.

One in particular may have new relevance today. In "The Midnight Sun," a painter struggles through a summer that will never end, cherishing what little water is available and watching neighbors try to flee to Canada to escape the heat as the Earth spirals closer to the sun.

The nightmare image that lingers is that of a painting of a waterfall that slowly melts and runs in the heat.

In a classic Serling twist, the woman recovers from a feverish delirium to find the world is moving away from the sun. Her world ends in ice instead of fire.

The debate over global warming is itself generating a lot of heat these days, but not much light.

Most experts agree that the average surface temperature has risen by a degree over the past century. But the agreement ends when we start talking about what the rise means, either for causes or for potential results.

The anecdotal evidence is compelling, but may be misleading. Phoenix, not a place known for mild summers, is reinventing the idea of "hot" this year.

The low last Tuesday was a chilly 96 degrees F. (Yes, that was the low, not the high.)

July's average high so far is 111 degrees.

Flip-flop sandals are melting on the ground.

And a woman who fainted and fell had to be taken to a burn unit after scalding her face on the pavement.

Yet all this evidence proves nothing about global conditions. Climate models give a good hint at global trends but fall far short of predicting whether Arkansas will have a hot summer, or if it will rain next week.

Here in the River Valley, the fields are still green in late July. Those of us bracing for six straight weeks of searing heat were delighted to wake up Tuesday to to a morning of rain, clouds and cool temperatures.

In short, we don't yet understand how the climate works or how much damage is caused by such activities such as burning fossil fuels. We can't even be sure that switching to hydrogen is a solution or another problem.

The certainty is that we live in a dangerously narrow balance. Too warm, and Mount Nebo becomes an offshore island. Too cold, and the glaciers are scraping their way to St. Louis again. But the dangers would begin far before either extreme.

Many civilizations have collapsed because of even natural changes in weather patterns. The Anasazi culture in the American Southwest was thriving until a 55-year drought struck. It never recovered.

Imagine what would have happened if the Dust Bbowl had lasted from the 1930s until the 1980s. Our nation, and the world, would be a very different place today.

We have no choice but to take the risks seriously, while dealing with them cautiously. In the meantime, funding should be provided for more studies of how climate works so that we can manage, or at least prepare, for future, inevitable climate changes.